In an image forming apparatus having a plurality of photosensitive members and capable of forming a color image, there has been known a technology of bringing a cleaning blade into contact with each photosensitive member and scraping toner remaining on a surface of each photosensitive member from the surface of each photosensitive member. There has also been known a technology of reducing friction, which is caused between the cleaning blade and the photosensitive member because the toner scraped from the surface of the photosensitive member by the cleaning blade stays at a contact part of the cleaning blade and the photosensitive member, and thus reducing a sound and a turn-up.
For example, there has been disclosed a configuration of the image forming apparatus having the cleaning blade contacted to each photosensitive member, in which a black image forming unit is configured to form a pattern image and to transfer the same to an intermediate transfer belt and image forming units corresponding to colors except for black are configured to reversely transfer toner of the pattern image from the intermediate transfer belt by a transfer bias having a reverse polarity to a printing process, at a timing except for the printing process.